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time, that it puflies up the Water from the Well 13 
Foot and a half high into the fucking Pipe. And 
when all the Pipes are full, if the Mercury be equal- 
ly high in both Shells, upon railing the Barrel one 
Inch, the Mercurj will rife 13,18 Inches in the outer 
Shelly which I call charging for forcing; becaufe in 
contitiuing to raife the Barrel, the forcing Valve im- 
mediately rifes, and the Water comes out at top 
during the reft of the Stroke, which is 12 Inches, 
and delivers f,6 Gallon of Water, Wine Meafure. 
Fi^. 10. reprefents the forcing Stroke half way up; 
with the 517 Inches in the outer Shell 4 Inches in 
the inner, and the whole fpace at bottom under the 
middle Cylinder 7 Inches. 
From this it appears, that in the whole Stroke of 
19 Inches in Length, there is only t of an Inch loft 
to charge for SuS:ion, and in the next ftroke, which 
is likewile of 13 Inches, there is only one Inch loft 
to charge for forcings fo that in a Motion of ^6 
Inches, there is but i t Inch, or about rl part inef- 
fetftual. But this is owing to the too large fpace of 
the outer Ihell, which contains 4 times more than the 
inner one, becaufe the Cylinders were only hammer'd, 
and not turn’d 5 for if the outer fpace had been no 
bigger than the inner, then 4 of an Inch of the ftroke 
would have charg’d for forcing; fo that only 4 an 
Inch in 2 6, or -4 part of the whole ftroke would have 
been ineffedlual 5 and in that Cafe, 4 of the Quanti- 
ty of Mercury, or a little more than iz Pounds, would 
have been fufticienr. 
There may ft ill lefs Mercury be us’d, if the mid- 
dle Cylinder be made of Plate Iron turn’d on the 
outftde, and bor’d within, the outer Cylinder bor’d, 
and the inner one turn’d ; fo that if the Work be 
well perform’d, eight or ten Pounds of Mercury will 
